There's 2 big differences between FB and G+ in terms of real names.
First, FB is really lax about enforcing its policy. Everytime they've started killing accounts (for example when they tried to purge all fake women) there's a huge public outcry when they stop. Often because they always screw up and purge tons of valid accounts, like G+ is doing now.
Secondly, G+ is linked to all your other google services. If google suspends your account you could lose your mail, calendar, contacts, etc. The loss of a fake FB accounts is much less risky than the loss of a fake G+ account. According to the reports I've read google is being inconsistent in their punishments for fake users. In some cases only the G+ profile is disabled, in some cases the whole account is frozen or destroyed.